NSC is good option to invest and have tax benifits under section 80 C. You can invest Rs 3000.00 PM but be care full every month’s investment is seperate investment and will be matured seperately. There is no maximum limit of investment in NSC. Further investment in PPF is also considerable from tax benifit angle. Maximum limit of investment is Rs 70000.00 and it can be invested in parts during the year also. In both the investment rate of return is also better than bank’s FDR.

As other have mentioned you have two options of investing in post office and their respective limits but they have not mentioned some critical differences between both these options.

1) NSC – National Saving Certificate – you can invest upto 1,00,000 each financial year and take benefit under 80c. But it is important to note that this investment will come with a 5 year lockin period and returns on investment will be taxable. Rate of return is less than PPF.

2) PPF – Public Provident Fund – You can invest upto 70,000 in each financial year. It comes with a long term lock in period and PPF account has a lockin period of 1 year. The rate of return is good. And the best part is returns are tax free.